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[Cloudera][ImpalaJDBCDriver](500593) Communication link failure. Failed to connect to server

Expert Contributor

hi community cloudera, 

we are verifying a strange behavior of an Impala connection controller on nifi, when the processor starts the connection, it displays the error below:

[Cloudera][ImpalaJDBCDriver](500593) Communication link failure. Failed to connect to server. Reason: Connection or outbound has closed

communication between hosts is ok, ports communicating without problem.

when we start and stop the processor the connection occurs without problem, this shows that the error is intermittent.

has anyone experienced this type of problem?


Master Collaborator

@yagoaparecidoti Welcome to the Cloudera Community. 

I understand that this connection failure between Impala JDBC Driver and NiFi is randomly disrupted.

Q. Are the other queries from Impala running fine?
Q. Version of NiFi and CDH/CDP?
Q. Is this specific only to the connection between NIFI and the Impala driver?
Q. May I know the size of the cluster?
Q. What are the values set for the following:
fe_service_threads and
Q. Do you also have TLS-enabled in the client communication?


Expert Contributor

hi @vaishaakb , 

1. Impala-shell queries work without any problems
2. Nifi version on CDP Public Cloud
3. the problem is in the impala connection controller on the nifi to the impala which is on another datahub
idle_session_timeout = no value
idle_query_timeout = no value
fe_service_threads = 64
idle_client_poll_time_s = this parameter does not exist in Impala
5. the environment is Kerberos and TLS enabled